Air toughened alloy steel



Patented May 2, 1933 UNITED STATES PATENT, oPFicE JOHN HOWE HALL AND JOSEPH S. COMERFORD, OF

HIGH BRIDGE, NEW JERSEY, As-

SIGNORS TO TAYLOR-WZELABTON IRON AND STEEL COMPANY, OF HIGH BRIDGE, NEW JERSEY, A CORPORATION OF NEW JERSEY Am TOUGHENED ALLOY STEEL,

in Drawing. Original application filed May 16, 1,927, Serial No. 1551,926. Divided and this application filed Septembe'1 "4, 1929. Serial No. 390,422. i

Our invention relates to the production and treatment of iron or steel alloys and more particularly to the production and treatment of manganese steel articles in cast, forged, rolled, wrought or drawn state, the nstant application being a division of application Ser. No. 191,926, filed May 16, 1927- (now Patent No. 1,732,202); the principal object tensile,

being to so treat the improved alloy of our invention that'articles made therefrom Wlll not require water quenching or other usual toughening treatment incidental to austenitic manganese steel, but may be toughened 1n the air. In extended experimentation, having for its ultimate object the production of sourid manganese steel articles qualified for service for which ordinary manganese steel is not suited, and in sizes much greater than heretofore has been attainable with known compositions and methods, we have discovered a steel alloy and method of treating it ,which possesses to a remarkable degreethe useful properties of austenitic manganese steel, fulfills the necessary requirements, and moreover readily responds to air toughening.

The air toughened steel of our invention may be identified as Steel A- r Preferred, Carbon. .Q .30 t0 85 to Nickel 1. to 5. 3." Manganese 10. to 15. 13.

Steel B \A I;

Preferred The physical properties of steel A are similar to those of ordinarymanganese steel, but the strength in both tension and compression isconsiderably lower and if the carbon is decreased the strength falls of? quite rapidly. In the case of the preferred composition of steel B the physical properties obtained on compression and bending tests apferr0 -chromeof which 1 ferro-chrome and;

per cent manganese,

proach quite closely .to those of ordinary manganese steel, but if either the chrome or Hence, we have found it essential for our purpose to sharply control the carbon and chrome content, either or both asthe rcase may be. Accordingly, in the one case, we use varying amounts of low carbon ferromanganese, and in the other case low carbon ferro-chrome. The use of ordinary 80% ferro-manganese to obtain all of the manganese required would result in too which as indicated is detrimental. So also, there would be'ari untoward result in the use of straight ferro-chrome.

Wehave successfully of the compositions stated, in the electric furnace, using as additions metallic nickel, part is low carbon which part must be low carbonferro-manganese. 1 V

The toughening of these steelsis accomphshed by heating or soaking and then cooltoughness of ordinary manganese steel and the property of hardening under cold work also characteristic of that'steel. The soak- 7 ing heat may range from'800 C. to1150 C.

. according so .such time as is necessary properly to conto relative metal "section, and for dition the article for quenching.

Havlng described our invention, we claim:

1 1. The method herein described, which consists in forming an article from a steel alloy composition containing ten to fifteen to five per cent metallic nickel, an effecting amount up to eight per cent chromium, about decimal thirty to decimal eighty-five per cent carbon, and about decimal fifty per cent silicon, soaking the article at a ranging from about 800 C. to about /1150 0., according to mass and relative metal section, to condition it "for quenching, and quenching in the air.

2. The method which consists in forming, a-steel alloy composition relatively low in carbon and containing ten to fifteenper ferro-manganese'- of temperature much carbon,

manufactured steel,

is f j ing them in the air. They'- then possess the an effective amount up cent manganese, from a melt including an effective amount up to five per cent metallic nickel and ferromanganese quantitatively suflicient to produce the range stated and v having a low order of carbon in order sharply to control the carbon content of the alloy, forming a shaped article from said composition, heating the article to quenching temperature, and quenching in air.

In testimony whereof we aflix our signatures.

' JOHN HOWE JOSEPH S. COMERFORD. 

